Canberra residents Claire and Kelly are delighted they can now get married - but may have to delay the wedding until after the birth of their twins, due in December.

Steve says he's been waiting 17 years to make "an honest man" of his life-long partner Matt. Their daughters aged 23 and 18 have never understood why their parents have not had the same rights as others and can't wait to get their dresses for the big event.

Making history

More than 100 people packed the public gallery and a nearby room where the debate was being screened as the ACT Legislative Assembly made history by becoming the first Australian jurisdiction to legalise same-sex marriage.

The Labor Government passed the bill with the support of Greens MLA Shane Rattenbury. The Canberra Liberals opposed it.

After the vote was counted the Gay and Lesbian Qwire burst into a rendition of Love is in the Air, people hugged and cheered and few tears were shed.

One supporter said he was surprised by the depth of emotion he felt on this "extraordinary day".

"I never thought I'd see this day," he said softly. "It's lovely to be legal".

Same rights

Lyn, 58, is thrilled she now has the same rights as her four brothers and sisters.

"It's freedom, freedom," she said, holding a placard reading 'THANK YOU ACT' decorated in bright rainbow colours. "Rights are so important - it's just the most wonderful thing."

Invitations are already being sent out for same-sex weddings in the ACT with the first ceremonies expected before Christmas.

Matt says he's inclined to wait until after the result of the Commonwealth High Court challenge against the new legislation but hopes to be attending friends' weddings in the meantime.

"Anyone who wants to get married has my full support," he said.

"We had a civil union in 2011," says Claire, "but it isn't the same thing. This [marriage] will be the next step for our family."